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| Titel |
A comprehensive evaluation of seasonal simulations of ozone in the northeastern US during summers of 2001–2005 |
| VerfasserIn |
H. Mao, M. Chen, J. D. Hegarty, R. W. Talbot, J. P. Koermer, A. M. Thompson, M. A. Avery |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 1 ; Nr. 10, no. 1 (2010-01-05), S.9-27 |
| Datensatznummer |
250007887
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| Publikation (Nr.) |
 copernicus.org/acp-10-9-2010.pdf |
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| Zusammenfassung |
| Regional air quality simulations were conducted for
summers 2001–2005 in the eastern US and subjected to extensive
evaluation using various ground and airborne measurements. A brief climate
evaluation focused on transport by comparing modeled dominant map types with
ones from reanalysis. Reasonable agreement was found for their frequency of
occurrence and distinctness of circulation patterns. The two most frequent
map types from reanalysis were the Bermuda High (22%) and passage of a
Canadian cold frontal over the northeastern US (20%). The model
captured their frequency of occurrence at 25% and 18% respectively.
The simulated five average distributions of 1-h ozone (O3) daily
maxima using the Community Multiscale Air Quality (CMAQ) modeling system
reproduced salient features in observations. This suggests that the ability
of the regional climate model to depict transport processes accurately is
critical for reasonable simulations of surface O3. Comparison of mean
bias, root mean square error, and index of agreement for CMAQ summer surface
8-h O3 daily maxima and observations showed –0.6±14 nmol/mol,
14 nmol/mol, and 71% respectively. CMAQ performed best in moderately
polluted conditions and less satisfactorily in highly polluted ones. This
highlights the common problem of overestimating/underestimating lower/higher
modeled O3 levels. Diagnostic analysis suggested that significant
overestimation of inland nighttime low O3 mixing ratios may be
attributed to underestimates of nitric oxide (NO) emissions at night. The
absence of the second daily peak in simulations for the Appledore Island
marine site possibly resulted from coarse grid resolution misrepresentation
of land surface type. Comparison with shipboard measurements suggested that
CMAQ has an inherent problem of underpredicting O3 levels in
continental outflow. Modeled O3 vertical profiles exhibited a lack of
structure indicating that key processes missing from CMAQ, such as lightning
produced NO and stratospheric intrusions, are important for accurate upper
tropospheric representations. |
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